JP2006509925A - Web zone stretching - Google Patents

Abstract

An apparatus and method for stretching one or more zones (IV) of the web (40) is disclosed. Webs that include stretched or activated zones are also disclosed. Each of the zones in the web is stretched in the cross-web direction (8), that is, in a direction (8) perpendicular to the down-web direction (8). The stretching can occur continuously as the web is being advanced through the device in the down-web direction. Stretching can occur in the absence of physical contact with the stretched zone of the web. The strain induced in the stretched zone can be introduced gradually over the stretch distance. Distortion can increase at the primary rate. The stretching method and apparatus may be used to activate an elastic zone in the web.

Description

  The present invention relates to the field of webs, web processing methods, and web processing devices. More specifically, the present invention provides an apparatus and method for stretching one or more zones of a web in the cross-web direction and a web so stretched.

  It may be desirable in many cases to stretch the web in the cross-web direction during processing. For example, a web comprising a layer of non-elastic material, such as a nonwoven web laminated to or otherwise affixed to the elastic layer, typically requires stretching to impart elasticity to the web. To do. When the web is stretched such that the inelastic layer or bond within the inelastic layer is broken or otherwise broken, it is stretched for one or more layers of elastic material placed within the web Leave an elastic web. Such stretching to impart elasticity to the web is commonly referred to as “activation” of the web (when the elasticity of the web is “activated” by stretching). Activation can be performed by various methods including, for example, tentering and ring rolling.

  Tentering typically involves gripping the edges of the web and stretching the web in the cross-web direction while advancing the web in the down-web direction (ie, along the length of the web). Although tentering provides the ability to change the amount of strain induced in the web, it also suffers from a number of disadvantages. For example, web edges often have to be discarded after tentering due to damage or inconsistent distortion in the web at the edges. Another potential disadvantage is that it is difficult or impossible to induce strain into selected portions or zones of the web using tentering. Furthermore, tentering devices can be costly and complex and may require a significant amount of floor space to operate.

  Ring rolling provides an alternative to tentering to stretch the web. Various ring rolling devices are described, for example, in US Pat. Nos. 5,143,679 (Weber et al.), 5,156,793 (Buell et al.), And 167, 897 (Weber et al.). While ring rolling can be used to stretch selected zones in the web, disadvantages of ring rolling include, for example, contact of the web with a ring rolling device that may undesirably affect the appearance of the web. May be included. The amount of strain that can be induced in a web using ring rolling may be limited by the ring rolling device. Adjusting or changing the amount of distortion may be difficult or limited. Furthermore, ring rolling devices typically must be stopped to achieve a change in the amount of distortion. In addition, ring rolling typically involves the rapid application of non-first order strain to the web, so that the web may tear or tear, thereby causing excessive waste.

  The present invention provides an apparatus and method for stretching one or more zones of a web and a web comprising one or more stretched zones. Each of the stretched zones in the web is stretched in the cross-web direction, i.e., transverse to the down-web direction. Stretching can occur continuously while the web is being advanced through the device in the down-web direction.

  It is one of the potential advantages of the method and apparatus of the present invention that stretching can occur in the absence of physical contact with the zone of the web being stretched. This lack of physical contact may prevent web marking during stretching. Further, contact with the stretched portion of the web during stretching may lead to web breakage or tearing, for example if the web is particularly brittle during stretching.

  Another potential advantage of the apparatus and method of the present invention is that strain induced on the stretched zone can be gradually introduced over the stretch distance so as to avoid rapid stretching that can result in tearing or breaking of the web. It is. In one approach, the method and apparatus of the present invention can provide strain that increases at a primary rate as opposed to non-primary induction of strain, for example, in ring rolling. The primary nature of the strain will help reduce the potential problems of web breaking or tearing due to the sudden application of strain.

  In another approach, the invention can be characterized in terms of strain rate, i.e., for example, the rate at which a strain of 1 (i.e. stretching by 100%) is induced is, for example, 20 meters per minute line The speed will be limited to 100 / min or less, more preferably 50 / min or less when the line speed is 20 meters / min. The strain rate in the method of the present invention will increase at a rate that is linearly proportional to the line rate. As a result, when the zone in the web is to be stretched by 100%, the strain rate using the method and apparatus of the present invention is more preferably below 500 / min when the line speed is 100 meters / min. Will be limited to 250 / min or less when the line speed is 100 meters / min.

  Another way in which the method and apparatus of the present invention can be characterized is by stretch distance. For example, the present invention will provide a stretch distance of 0.2 meters or more, preferably 0.4 meters or more, and even 0.5 meters or more. Within the stretch distance, only a portion of the web is activated or stretched (eg, as opposed to a tentering method and apparatus in which the web is stretched substantially end to end of its full width).

  Another potential advantage of the apparatus and method of the present invention is that the amount and / or strain rate can be easily adjusted even while the web is being processed. The ability to adjust strain and / or strain rate while the web is moving in the down-web direction is, for example, monitoring strain, strain rate, or other characteristics to achieve a desired strain level in the stretched web. This is particularly useful when integrated with a feedback control system that maintains The web will be attached to the device without inducing any strain, and it may also be useful for starting the method as the amount of strain may continue as the web moves in the down-web direction. .

  Another potential advantage can be found, for example, in the ability to stretch all of a much wider stretched in-zone web than is possible with ring rolling methods and equipment. In one aspect, it would be possible to stretch all in-zone webs having a width of 5 millimeters or more prior to stretching. In another aspect, the zone of the web surrounding the stretched zone is the same as the stretched zone (which itself may be more than 5 millimeters wide before stretching as described above) or It will be wider than that.

  The stretching apparatus and method of the present invention can be used to “activate” the zones in the web such that the activated zone exhibits elasticity after activation. As described above, stretching the web such that the inelastic layer or bond within the inelastic layer is broken or otherwise broken, thereby, for example, thanks to an elastic material placed in the web Leave the stretched part of the elastic web at. As used herein, an inelastic zone in a web is “activated” after stretching when it is stretched such that the stretched zone of the web exhibits elastic behavior. Elastic behavior means that after stretching of the activated zone, the activated zone substantially returns to its relaxed dimension if there is no constraint.

  In one aspect, the present invention provides a method for stretching a web by advancing a web having a width in a cross-web direction transverse to the down-web direction in the down-web direction. The web includes first, second, and third zones, each of the first, second, and third zones includes a portion of the width of the web and extends along the length of the web in a down-web direction. The second zone is located between the first zone and the third zone. The method further comprises stretching the second in-zone web in the cross-web direction over the stretch distance while advancing the web in the down-web direction, wherein the stretching is in both the down-web direction and the cross-web direction. And changing the position of the first zone and the third zone relative to each other in the direction of stretching across. In this method, all of the web in the second zone is stretched and the second zone has a width of 5 millimeters or more prior to stretching.

  In another aspect, the present invention provides a method for stretching a web by advancing a web having a width in a cross-web direction transverse to the down-web direction in the down-web direction. The web includes first, second, and third zones, each of the first, second, and third zones includes a portion of the width of the web and extends along the length of the web in a down-web direction. The second zone is located between the first zone and the third zone. The method further comprises stretching the second in-zone web in the cross-web direction over the stretch distance while advancing the web in the down-web direction, wherein the stretching is in both the down-web direction and the cross-web direction. Changing the position of the first zone and the third zone relative to each other in the direction of stretching perpendicular to. Stretching by 100% of the web in the second zone induces a strain rate of less than 100 per minute while advancing the web in the down-web direction at a line speed of 20 meters per minute, the strain rate being linear to the line speed Increases at a proportional rate.

  In another aspect, the present invention provides a method for stretching a web by advancing a web having a width in a cross-web direction transverse to the down-web direction in the down-web direction. The web includes first, second, and third zones, each of the first, second, and third zones includes a portion of the width of the web and extends along the length of the web in a down-web direction. The second zone is located between the first zone and the third zone. The method further comprises stretching the second in-zone web in the cross-web direction over the stretch distance while advancing the web in the down-web direction, wherein the stretching is in both the down-web direction and the cross-web direction. Changing the position of the first zone and the third zone relative to each other in the direction of stretching perpendicular to. Changing the position of the first zone relative to the third zone includes linearly increasing the difference in the position of the first zone relative to the third zone in the stretching direction over the stretching distance.

  In another aspect, the present invention provides a web stretching apparatus. The apparatus includes a web path having a down-web direction extending from the input end to the discharge end and a cross-web direction transverse to the down-web direction, wherein the web paths are first, second, and third. Defining a zone, each of the first, second, and third zones including a portion of the width of the web path and extending along the length of the web path in a down-web direction; Includes a web path located between the first zone and the third zone. The first zone and the third zone may be in a neutral position relative to each other where the first, second, and third zones are aligned in the cross-web direction. The first zone and the third zone are alternately present at stretch positions relative to each other where the first and third zones are displaced from each other in a stretch direction that is perpendicular to both the down-web direction and the cross-web direction. Also good. The web path further defines a stretch distance in which the first zone and the third zone are displaced relative to each other in the stretch direction. The second zone of the web path extends between the first zone and the third zone and is not supported between them for the stretch distance.

  In another aspect, the present invention is a web having an indefinite length and a width in a cross-web direction transverse to the length, the web further comprising first, second, and third zones, Each of the first, second, and third zones provides a web that includes a portion of the width of the web and extends along the length of the web. The second zone is located between the first zone and the third zone. The second zone is an activated elastic zone with a width of 5 millimeters or more when in the relaxed state. The first zone has a width that is greater than or equal to the width of the second zone when in the relaxed state.

  In another aspect, the present invention is a web having an indefinite length and a width in a cross-web direction transverse to the length, the web further comprising first, second, and third zones, Each of the first, second, and third zones provides a web that includes a portion of the width of the web and extends along the length of the web. The second zone is located between the first zone and the third zone. The second zone is a stretched zone having a width of 5 millimeters or more after being stretched from the original width. The first zone has a width that is greater than or equal to the width of the second zone.

  These and other features and advantages of the apparatus and method of the present invention will be described below with respect to exemplary embodiments of the present invention.

  FIG. 1 is a plan view of an embodiment of a zone stretching apparatus according to the present invention. The apparatus includes a series of belts 10, 20, and 30 that define a web path represented by arrow 8 in the down-web direction. Although the web moving along the web path may actually be wider than the web path as defined by the outermost belts 10 and 30, the web path will cross the side defined by the outermost belts 10 and 30 to the web path. Include on the edge of. In addition to defining the down-web direction, the arrow 8 can also be used to define a cross-web direction transverse to the down-web direction.

  In use, the belt 10 rotates so that its upper surface 18 moves in the direction of arrow 8 but its lower surface (not shown) moves in the opposite direction. The belt 10 includes an input end 12 and a discharge end 14. Similarly, belt 20 includes an input end 22 and a discharge end 24 with an upper surface 28 that moves in the direction of arrow 8 and a lower surface (not shown) that moves in the opposite direction. Similarly, the belt 30 includes an input end 32 and a discharge end 34 with an upper surface 38 that moves in the direction of arrow 8 and a lower surface (not shown) that moves in the opposite direction.

  At the same time, the input and discharge ends of belts 10, 20 and 30 define the corresponding input and discharge ends of the web path defined by the belt. Also, the x-axis is aligned with the down-web direction depicted by arrow 8, the y-axis is aligned with the cross-web direction (perpendicular to the down-web direction), and the orthogonal x and y reference axes are in FIG. It can be seen. Although not seen in FIG. 1, it will be appreciated that the third reference axis, ie, the z axis may be defined as a reference axis that is perpendicular to both the x and y reference axes. The z-axis is depicted in connection with FIGS.

  The placement of belts 10, 20, and 30 along the web path is such that belt 10 defines zone I, belt 20 defines zone III, belt 30 defines zone V, and defines a zone within the web path. Can be characterized as Although not necessarily required, it may be preferred that at least some separation or space be provided between adjacent belts. In the depicted embodiment, the space between belts 10 and 20 defines zone II in the web path, and the space between belts 20 and 30 defines zone IV in the web path. Zones II and IV typically function as stretching zones in the web path, ie, zones where all or substantially all stretching occurs during processing. Each of the zones can be described as occupying part of the width of the web path, and preferably extends from the input end to the discharge end for the length of the web path.

  Typically, each of those zones has a cross-web width of 5 millimeters or greater, and all of the zones II and IV webs are stretched. While it may be preferable for Zones II and IV to be stretched simultaneously, it is not required. Alternatively, only one of zones II and IV may be activated.

One way in which the present invention can be characterized when compared to conventional stretching methods such as ring rolling is in terms of strain rate. As used herein, it is understood that strain is itself a unit without dimensions (since strain is measured as a change in the length of the article divided by the original length of the article before stretching) The strain rate is a strain per unit time. For the present invention, the strain rate may be measured by the following equation:
(Change in length / original length) / (stretching distance / line speed)

  For example, if the zone in the web is to be stretched by 100%, that is, if the change in length is equal to the original length (thus doubling the length of the article in the stretch direction) The strain rate using the method and apparatus of the present invention is limited to 100 / min or less when the line speed is 20 meters / min, more preferably 50 / min or less when the line speed is 20 meters / min. It may be. The method and apparatus of the present invention can achieve such strain rates over stretch distances of 0.2 meters or more.

  In comparison, a ring rolling method (e.g., Weber et al.) Using a 3.3 millimeter (0.14 inch) overlap and a 3.8 millimeter (0.15 inch) peak-to-peak groove pitch meshing step roll. U.S. Pat. No. 5,143,679) to 38 meters to achieve a strain rate of 100 / min at the same stretch distance, and thus a line speed of 20 meters / min. A roll of (125 feet) diameter would be required. It will be appreciated that a roll of that size is essentially impossible to construct and operate in a safe and / or effective manner or in a feasible economics according to known engineering principles. Let's go.

  While the method and apparatus of the present invention provides a strain rate that is significantly lower than, for example, ring rolling, at relatively low line speeds, the decrease in strain rate becomes more pronounced as the line speed increases. For example, when the web is to be stretched by 100%, the strain rate using the method and apparatus of the present invention is less than 500 / min, more preferably the line when the line speed is 100 meters / min. It may be limited to 250 / min when the speed is 100 meters / min. Conventional with interlocking step rolls having a diameter of 0.2 meters (8 inches) with an overlap of 3.3 millimeters (0.13 inches) and a peak-peak pitch of 3.8 millimeters (0.15 inches) Operating the ring rolling device at the same line speed will result in strain rates in excess of 1100 / min. This increased strain rate is mainly due to the short stretch distance provided by conventional ring rolling equipment.

  The strain rate increases at a rate proportional to the line speed. In the context of the present invention, the strain rate may increase at a rate that is linearly proportional to the line rate. In contrast, the strain rate of the ring rolling method increases at a rate that is not linearly proportional to the line speed. As a result, higher line speeds can lead to even more dramatic differences between the method and apparatus of the present invention and the ring rolling method. For example, the present invention can provide a strain rate of 1500 / min or less when the line speed is 300 meters / min, and preferably a strain rate of 750 / min or less when the line speed is 300 meters / min. .

  The strain rate is also inversely proportional to the stretch distance, and increasing the stretch distance results in a lower strain rate. For example, the method and apparatus of the present invention having an extension distance of 0.2 meters or more is 100 / min or less when the line speed is 20 meters / minute and 500 / minute when the line speed is 100 meters / minute. Alternatively, a strain rate of 1500 / min can be provided when the line speed is 300 meters / min or less. In another set of examples, the method and apparatus of the present invention having an extension distance of 0.4 meters or more is 50 / min or less when the line speed is 20 meters / minute, and the line speed is 100 meters / minute. It can provide a strain rate of 250 / min or less at some time, or 750 / min when the line speed is 300 meters / min.

  The following table provides a range of strain rates (per minute) for 100% stretch at various distances and line speeds that can be achieved using the present invention. Although some embodiments of the present invention may not provide a first order relationship, it may be preferred that the relationship is first order as can be seen from the values in the table.

  Another way in which the method and apparatus of the present invention can be characterized is by stretch distance. For example, the present invention can provide any desired length, for example, a stretch distance of 0.2 meters or more, 0.5 meters or more, 0.75 meters or more. Within that stretch distance, only a portion of the web is activated or stretched (eg, as opposed to a tentering method and apparatus in which the web is stretched across its full width). Within the selected stretch distance range, virtually any selected amount (eg, 100%) of activation or stretching in only the selected zone can be achieved.

  In contrast, a ring rolling process that provides 100% stretch using 3.3 millimeter (0.13 inch) overlap and 3.8 millimeter (0.15 inch) peak-to-peak pitch meshing step rolls. Requires a roll of 38 meters (125 feet) diameter to achieve a 0.2 meter stretch distance or 114 meters (375 feet) diameter to achieve a 0.4 meter stretch distance Will. Such sized rolls are essentially impossible to construct and operate in a safe and / or effective manner according to known engineering principles or with feasible economics.

  The method and apparatus of the present invention can alternatively be characterized by the relationship between the width of the stretching zones and the surrounding zones. In essence, it may be preferred that the unstretched zone has a width that is greater than or equal to the width of the stretched zone. This is especially true when the unstretched zone is located between two stretched zones where all of the web is stretched. For example, in a five-zone web where the portion of the web in Zone II is stretched, Zone I may preferably have a width that is greater than or equal to the width of Zone II. It is also preferred that Zone III has a width that is greater than or equal to the width of Zone II, and that Zone III has a width that is greater than or equal to the width of Zone IV (where Zone IV is also a stretched zone). It may be. It may be further preferred that zone V has a width that is greater than or equal to the width of zone IV.

  Although the depicted apparatus includes five zones arranged across the width of the web path, it will be appreciated that the invention may be practiced with as few as three zones. For example, belts 10 and 20 could be used without belt 30 to provide a web path defined by zones I, II, and III. It should also be understood that a web path having more than 5 zones arranged across the width of the web path may be provided.

  2 is a cross-sectional view of the apparatus of FIG. 1 taken along line 2-2 of FIG. Belt 20 is stretched over pulleys 23 and 25, and belt 20 includes pulley 23 at its input end 22 and pulley 25 at its discharge end 24. Belt 20 includes an upper surface 28 and a lower surface 26, the two surfaces moving in opposite directions as belt 20 rotates about pulleys 23 and 25. Although the input and output end pulleys are depicted as having similar diameters, it should be understood that the size of the pulleys may vary.

  Since it is partially hidden by the belt 20 and its pulleys 23 and 25, the input end of the belt 30 (and its associated pulley) is hidden behind the input end 22 of the belt 20 and its pulley 23, and the belt 30 and Only a portion of the support structure is shown in FIG. However, the discharge end 34 of the belt 30 can be seen in FIG. 2 along with a pulley 35 located at the discharge end 34 of the belt 30. Both the lower surface 36 and the upper surface 38 of the belt 30 can also be seen in FIG. 2, the two surfaces moving in opposite directions during operation of the device.

  The discharge end 24 of the belt 20 is shown as having some displacement in the z-axis direction with respect to the belt 30. It is this displacement that provides for stretching of the web processed by the apparatus as described in more detail herein with respect to FIGS. Typically, it would be preferable to displace only one end of the belt at its discharge end while maintaining all relative positions of the belt at the input end.

  Since belts 20 and 30 are displaced from each other in the z-axis, in some cases it may be desirable to operate one belt at a faster or slower speed to adjust to different web path lengths in different zones. . For example, in devices such as those depicted in FIGS. 1 and 2, the web path length in zone III is different from the web path length in zones I and V. As a result, it may be desirable to operate belt 20 at a slightly higher down-web speed as compared to Zones I and III belts 10 and 30. Alternatively, it is desirable to modify the web path length in different zones so that all of the zones have the same (or nearly the same) path length so that no adjustment of web speed in the different zones is required. Sometimes.

  Although the device of the present invention is depicted as relying on the use of a continuous belt wound around a rotating pulley, it is understood that other alternative structures may be used in place of the continuous belt. Will be understood. For example, a series of rollers may be used that may preferably have a relatively small diameter so that the rollers can be placed without spacing. In other cases, it may be possible to use a continuous belt that combines rollers with other structures to support and / or hold the web during processing.

  FIG. 3 is an end view of FIG. 1 with the web 40 positioned along the web path and the web 40 in contact with the top surfaces 18, 28, and 38 of the belts 10, 20, and 30, respectively. FIG. 3 also depicts zones I, II, III, IV, and V in addition to both the y and z reference axes.

  The view as seen in FIG. 3 was taken before any displacement of one or more belts was applied in the z-axis direction. In this arrangement, the belts and their respective zones can be described as being in a neutral position relative to each other, i.e., no cross-web stretching is being induced in the web 40.

  The web 40 can be any web where stretching in the cross-web direction is desired (corresponding to the y-axis as seen in FIG. 3). The depicted web 40 is a laminate that includes a first layer 45 and a second layer 46. The first and second layers 45 and 46 may be the same or different. It may be preferred that the second layer 46 comprises an elastic material (eg, sheets, filaments, strands, etc.) so that the layer 46 can provide elasticity to the web 40. It may be preferred that the first layer 45 be inelastic (eg, non-woven material). A preferred web 40 may include an inelastic layer 45 laminated to the elastic layer 46 so that the web 40 is generally substantially inelastic before stretching.

  As a result of stretching, the bond in the inelastic layer is broken or otherwise broken, thereby allowing the elasticity of the layer 46 to spread within the stretched zone so that the web 40 is within the stretched zone. Can be elastic. As described herein, a zone that is stretched may be described as an activation zone to indicate that the potential elasticity of the zone has been activated.

  Although the web 40 is depicted as a multi-layer structure, it will be understood that the web 40 may include any number of layers, structures, materials, etc. as desired. Furthermore, the portion of the web 40 may be totally inelastic, i.e. the portion of the web 40 may not contain any significant amount of elastic material. For example, web 40 may preferably include a non-elastic web component in zones I, III, and V and a non-woven / elastic web laminate in zones II and IV. Another example of a multi-component web is described below in connection with FIG.

FIG. 4 is an end view of the device as seen in FIG. 3, however, with the belt 20 displaced in the z-axis direction above the distance d _z (see FIG. 2 for a side elevation view of the displacement). . The figure is taken from the discharge end of the apparatus, and the lower end 26 of the belt 20 can be seen in FIG. 4 since the input end of the belt 20 remains aligned with the input ends of the belts 10 and 30.

  As a result of the displacement of the discharge end 24 of the belt 20 in the z-axis direction, the webs 40 in zones II-IV are lifted relative to the portion of the web 40 in zones I and V (on belts 10 and 30). . With this displacement, the distance between the edge of the belt 10 and the edge of the belt 20 is increased (similar to the distance between the collar of the belt 20 and the collar of 30), and the belt 20 is displaced in the z-axis direction. Therefore, the portions of the webs 40 in the zones II and IV are stretched. In a non-contact stretching method and apparatus, such as that shown, the zone II web fills in the z-direction height difference between belts 10 and 20 in zones I and III. Similarly, the zone IV web fills in the z-direction height difference between belts 20 and 30 in zones III and V.

  When the discharge end 24 is displaced as seen in FIGS. 2 and 4, the web as the point on the web 40 moves from the input end to the discharge end of the device due to the gentle slope of the belt 20 relative to the belts 10 and 30. The amount of distortion induced by 40 increases gradually. If the belt moves in a straight path between the input end and the discharge end as seen in FIG. 2, the variation in distortion from the input end to the discharge end may be described as primary.

  FIG. 2 also illustrates the stretch distance, i.e. the distance by which a selected zone of the web is stretched. Typically, the stretch distance is defined by the distance between the input ends 12, 22, and 32 and the discharge ends 14, 24, and 34 of the belts 10, 20, and 30.

  The stretching distance may in some cases preferably be greater than or equal to the width of the stretched zone of the web. Thus, in the illustrated method and apparatus, the stretch distance can preferably be greater than or equal to the width of zones II and IV. Alternatively, it may be preferred that the stretch distance as a whole is greater than or equal to the width of the web. In another way of characterizing the stretch distance, it may be preferred that the stretch distance is as large as or greater than twice the width of at least one of the stretched zones in the web. For example, in the depicted embodiment, it may be preferred that the stretch distance be greater than twice the width of Zone II. In some cases, the relationship between the stretch distance and at least one width of the stretched zone is such that the stretch distance is greater than or equal to 4 times the width of the associated stretch zone. For example, in the depicted embodiment, it may be preferable for the stretch distance to be greater than four times the width of Zone II.

  In the apparatus depicted in FIG. 4, the belts 10, 20, and 30 preferably include some structure or material on their surface that serves to hold the web 40 in contact with the belt surface. Sometimes. For example, the belt surface may include mechanical structures such as portions of hook and loop structures that hold the replenishment web 40 thereon during processing. Alternatively, belts 10, 20, and 30 may hold web 40 by other techniques including, but not limited to, adhesives, magnetic forces, and the like. In other cases, materials that increase the coefficient of friction between the web 40 and the belts 10, 20, and 30 may be used, such as abrasives, rubber, and the like. Yet another alternative involves providing structures such as pins, struts, pyramids, etc. protruding on the belts 10, 20, and 30 to improve their ability to hold the web thereon. Sometimes.

FIG. 5 is an end view of the apparatus of FIGS. 3 and 4, however, with the belt 20 further displaced in the z-axis direction above the distance d _z . Since the view seen in FIG. 5 is a view of the discharge end of the device, the lower surface 26 of the belt 20 is also seen in FIG. Increased displacement of belt 20 in the z-axis direction relative to adjacent belts 10 and 30 results in increased distortion of zone II and IV inner web 40 (compared to the amount of distortion provided in FIG. 4).

  Changing the displacement of the belt 20 relative to the adjacent belts 10 and 30 between FIGS. 3-5 also illustrates the adjustability of the method according to the invention. For example, the web can be easily loaded into the device while the belts 10, 20, and 30 are in their neutral positions as seen in FIG. 3 (the belts are aligned) The displacement can be gradually increased as it moves in the down-web direction. Further, adjusting the displacement of the belt 20 relative to one or both of the belts 10 and 30 while the web 40 is moving in the down-web direction to adjust the amount of strain induced in the zone of the web 40. Can do.

  FIG. 6 is an enlarged cross-sectional view of the web 40 after the stretching-related forces as depicted in FIGS. 4 and 5 have been removed and thus have relaxed the stretched zone. Web 40 includes layers 45 and 46 and may be defined by zones I-V as described above. In zones II and IV, ie zones where the web 40 has been stretched as depicted in FIGS. 4 and 5, the web 40 will have some as depicted in FIG. 6 if the stretched zone is now elastic. May indicate gathering or habit.

  In connection with FIG. 6, it would be possible to characterize a web according to the invention comprising one or more stretched zones. Such a web 40 may have an indefinite length, i.e. a length much greater than its width, for example it may be collected on a roll or immediately led to a conversion process, where the web 40 is It can be cut into strips, sheets, etc. for incorporation into another product. Webs produced according to the present invention will be characterized in terms of their stretched zones. For example, a web according to the present invention has a width of at least one of the stretched zones when in a relaxed state (after removing the stretching force) in the cross-web direction of 5 millimeters or more, and in some cases 10 millimeters or more. May include one or more stretched zones.

  All of the web in the stretching zone is stretched. The feature is that the stretched zone in the web of the present invention is such that the portion of the web that is in contact with the meshing teeth is not typically stretched during processing, thus creating a small area within the larger stretched zone. Distinguish from ring-rolled webs that remain unstretched.

  Further, as also described herein, the zone where no stretching is performed may be the same as or wider than the stretching zone. Also, two stretching zones may be provided on the opposite side of the zone where no stretching is provided. For example, see Zones II-IV of web 40. In such an embodiment, all of the zones, i.e. the two stretched zones and the intermediate zone, may have a width of 5 millimeters or more.

  For example, if a stretched zone in a web, such as web 40 described above, exhibits elasticity after stretching, the zone may be referred to as an “activated” zone within the principles of the present invention. However, in some cases, the stretched zone in the web of the present invention may not exhibit elasticity after stretching. Such zones may be stretched, for example, to provide molecular orientation, thinning, and the like.

  7 and 8 depict an alternative device according to the present invention. The device depicted in FIGS. 7 and 8 is similar in many respects to the device depicted in FIGS. The apparatus also includes a belt that defines a series of zones that occupy a portion of the web path in the cross-web direction.

  However, the apparatus of FIGS. 7 and 8 includes a pair of opposing belts that secure or otherwise constrain the inner web 140 of zones I, III, and V, respectively. For example, belts 110 and 210 in Zone I secure the portion of web 140 within Zone I and hold web 140 between the two belts. Similarly, the lower belt 120 is combined with the upper belt 220 to hold the zone III inner web 140. Similarly, the lower belt 130 is combined with the upper belt 230 to fix the web 140 in the zone V. As in the apparatus of FIGS. 1-5, zones II and IV of the web 140 are not constrained by or in contact with any belt.

  FIG. 8 depicts the apparatus of FIG. 7 with zone III of web 140 displaced in the z-axis direction by lower belt 120 and upper belt 220. Zone II and IV inner webs are stretched for retention of zone I inner web 140 by lower belt 110 and upper belt 210. Similarly, on the opposite side of Zone III, belts 130 and 230 constrain the Zone V inner web during stretching of Zone II and IV inner web 140.

  The portion of the inner web in each of zones I, III, and V may be constrained exclusively by the pressure between the pair of opposing belts, but one or both of the upper and lower belts in each of zones I, III, and V It may include structures or materials that assist in holding the web 140 between a pair of opposing belts.

  Further, the pressure between the pair of opposing belts may be generated by various techniques. For example, in some cases, the pressure provided by the belt tension may be sufficient without providing any intermediate support structure between the input and output ends of the belt. In other cases, it may be desirable to provide an intermediate support between the input and output ends of the belt to maintain sufficient pressure on the web that is secured between the opposing belts during operation of the device. Sometimes. Such intermediate supports may take the form of static structures (eg, surfaces over which bolts ride) or dynamic structures (eg, intermediate support rollers).

  For example, a temperature control device 180 that may be arranged to control the temperature of the webs 140 in zones II and IV during processing is also depicted in FIGS. The temperature controller 180 may be used to heat and / or cool the web 140 during stretching as desired.

  FIG. 9 depicts another alternative device that includes a pair of opposing belts 310 and 410 in Zone I and a pair of opposing belts 330 and 430 in Zone V. A narrower zone III inner belt 320 used to displace the web 340 in the z-axis direction compared to the zone I and V inner web 340 portions is placed between a pair of opposed belts. In the arrangement seen in FIG. 9, it may not be necessary to constrain the web 340 in zone III, but the portions of web 340 in zone II and IV are stretched due to the displacement of web 340 in zone III. .

  One aspect depicted in FIG. 9 is that not all of their corresponding zones in the belt and web need be uniform in size. The width of the zone in the cross-web direction can vary from zone to zone as required. Another aspect depicted in FIG. 9 is that because of the greater force that can occur in a narrower web zone (eg, zone III in FIG. 9), the narrower zone can be locked to hold or constrain the web therein. It may not be necessary.

  FIG. 10 is a block diagram illustrating the concept that the web processing device 60 used to stretch a portion of the web can be used in-line with other web processing devices. For example, the web processing device 60 may process an existing web, for example, by heating, cooling, calendering, applying material to an existing web (eg, applying a hot melt or pressure sensitive adhesive to the web), and the like. It may be placed downstream of the device 50 which may be. In some cases, apparatus 50 may produce a web (eg, by extrusion, rotational bonding, carding, meltblowing, weaving, lamination of a nonwoven web or other inelastic web to an elastic web, etc.) The web is then introduced into a web processing apparatus according to the present invention.

  The web processing device 60 according to the present invention may itself be placed upstream of another processing device 70 that acts on the web after a portion of the web has been stretched according to the principles of the present invention. For example, the device 70 can slit the web at one or more locations, puncture and / or open, roll the web into a sheet, apply the adhesive to the web, and laminate the material to the web. It may be used for (for example, attaching a mechanical fastener material such as a hook), die cutting, and the like.

  The device 70 may also be used to maintain the web in its stretched state for a desired residence time during which the web or portion of the web may undergo additional processing. For example, it may be desirable to raise and / or lower the temperature of a web or web portion in a controlled manner. The residence time may be maintained, for example, using a belt or other structure that maintains a constant level of stretching as induced by the apparatus described above with respect to FIGS.

  As briefly mentioned above, the present invention can be used to process any suitable web, including homogeneous single layer webs, multilayer webs, composite webs, and the like. A suitable web is schematically illustrated, for example, as a single multilayer web in FIG. An example of a composite web that may be processed using the apparatus and method of the present invention is depicted in FIG. Web 440 of FIG. 11 is a composite web of various different components laminated together (with the cross-sectional view of the web depicted in FIG. 11).

  Various zones are identified in relation to the web 440 (for convenience) corresponding to the zones described in connection with the apparatus of FIGS. 1-8 above. In web 440, zones I and V each contain an adhesive layer 441 on substrate 442. By constraining the web 440 within the opposing belt as described in connection with the apparatus of FIGS. 7 and 8, the integrity of the adhesive layer 441 will be better maintained.

  Zone III of web 440 contains a layer 443 (eg, a layer of hook material for hook and loop fasteners) used for mechanical fasteners. As with the adhesives found in zones I and V, it is desirable to prevent any significant amount of stretching in zone III of the web in order to maintain the integrity of the mechanical fastener material 443 placed therein. I will.

  Zones II and IV of web 440 contain a laminate that includes a non-elastic cover layer 445 on both sides of a layer of elastic material 446 (the non-elastic cover layer 445 is only provided on one side of layer 446 of elastic material 446). It is understood that it may be.) Cover layer 445 will typically constrain elastic layer 446 in both the down-web and cross-web directions until stretched to release their inelastic bond. However, when processed using the apparatus and / or method of the present invention, the inelastic bond in the cover layer 445 is separated, thereby allowing the webs in zones II and IV to cross-web direction thanks to the elasticity of the layer 446. Make it elastic.

  After processing according to the principles of the present invention, the web 440 is separated within Zone III, each of which has an adhesive component (Zone I or V), an elastic component (Zone II or IV), and a mechanical fastener component (part of Zone III). The web 440 can be directed into a slitter or other separation device to result in two webs containing. These webs are then rolled into sheets for use in a variety of products including, but not limited to, children's diapers, adult incontinence equipment, bedding (eg, sheets, pillow cases, etc.), apparel, etc. Can do.

  The preceding specific embodiments illustrate the practice of the present invention. The present invention may be suitably implemented in the absence of any element or item not specifically described in this document.

  Various modifications and alterations of this invention will become apparent to those skilled in the art without departing from the scope of this invention, and the present invention is unduly limited to the exemplary embodiments described herein. It should be understood that it is not to be limited by the limitations set forth in the claims and any equivalents of those limitations.

1 is a plan view of an apparatus according to the present invention. FIG. 2 is a cross-sectional view of the apparatus of FIG. 1 taken along line 2-2 of FIG. FIG. 2 is an elevation view of the discharge end of the apparatus of FIG. 1 with a web 40 placed on the apparatus. FIG. 3 is an elevational view of the discharge end of the apparatus of FIG. 1 with a web 40 placed thereon and the belt 20 occupying zone III displaced from the belts 10 and 30 in the z-axis direction. FIG. 2 is a diagram of the apparatus of FIG. 1 depicting further displacement of the belt 20 in the z-axis direction. FIG. 6 is an enlarged cross-sectional view of the web of FIGS. 3-5 after stretching and relaxation. FIG. 4 is an end view of the discharge end of an alternative device according to the present invention in which the web 140 is constrained between a pair of opposing belts in zones I, III, and V. FIG. 8 is a diagram of the apparatus of FIG. FIG. 6 is an elevation view of the discharge end of another alternative device according to the present invention. 1 is a block diagram of one system incorporating a web stretching apparatus according to the present invention. 1 is a cross-sectional view of a web that can be processed using the apparatus and / or method of the present invention.

Claims (34)

Advancing a web having a width in a cross-web direction transverse to the down-web direction in the down-web direction, the web further comprising first, second, and third zones; Each of the first, second, and third zones includes a portion of the width of the web and extends along the length of the web in a down-web direction, the second zone being the first zone A process placed between the third zone;
Stretching the web in the second zone in the cross-web direction over a stretch distance while advancing the web in the down-web direction, wherein the stretching is in both the down-web direction and the cross-web direction. A method of stretching the web comprising the steps of: changing the position of the first zone and the position of the third zone with respect to each other in a vertical stretching direction,
A method wherein all of the web in the second zone is stretched and the second zone has a width of 5 millimeters or more prior to the stretching. Advancing a web having a width in a cross-web direction transverse to the down-web direction in the down-web direction, the web further comprising first, second, and third zones; Each of the first, second, and third zones includes a portion of the width of the web and extends along the length of the web in a down-web direction, the second zone being the first zone A process placed between the third zone;
Stretching the web in the second zone in the cross-web direction over a stretch distance while advancing the web in the down-web direction, wherein the stretching is in both the down-web direction and the cross-web direction. A method of stretching the web comprising the steps of: changing the position of the first zone and the position of the third zone with respect to each other in a vertical stretching direction,
Stretching the web in the second zone by 100% induces a strain rate of less than 100 per minute while advancing the web in the down-web direction at a line speed of 20 meters per minute, A method in which the speed increases at a speed that is linearly proportional to the line speed. Advancing a web having a width in a cross-web direction transverse to the down-web direction in the down-web direction, the web further comprising first, second, and third zones; Each of the first, second, and third zones includes a portion of the width of the web and extends along the length of the web in a down-web direction, the second zone being the first zone A process placed between the third zone;
Stretching the web in the second zone in the cross-web direction over a stretch distance while advancing the web in the down-web direction, wherein the stretching is in both the down-web direction and the cross-web direction. A method of stretching the web comprising the steps of: changing the position of the first zone and the position of the third zone with respect to each other in a vertical stretching direction,
Changing the position of the first zone relative to the third zone includes linearly increasing the difference in position of the first zone relative to the third zone in the direction of stretching over the stretch distance.   The method according to claim 1, wherein the stretching activates the second zone such that the second zone exhibits elasticity after stretching. Clamping the web in the first zone between opposing belts while stretching the web in the second zone over the stretching distance;
The method of any one of claims 1 to 4, further comprising clamping the web in the third zone between opposing belts while stretching the web in the second zone over the stretching distance. .   6. The method of claim 5, wherein over the stretch distance, the web in the second zone spans between the opposing belts clamping the web in the first zone and the web in the third zone.   The method according to claim 1, wherein the first zone has a width that is equal to or greater than the width of the second zone before stretching.   The method according to claim 1, wherein the third zone has a width that is equal to or greater than the width of the second zone before stretching.   Stretching the web in the second zone by 100% induces a strain rate of 100 per minute or less while advancing the web in the down-web direction at a line speed of 20 meters per minute, 9. The method of any one of claims 1 or 3-8, wherein the method increases at a rate that is linearly proportional to the line speed.   Stretching the web in the second zone by 100% increases the strain rate at a rate that is linearly proportional to the line speed and advances the web in the down-web direction at a line speed of 20 meters per minute. 9. A method as claimed in any one of the preceding claims, inducing a strain rate of not more than 50 minutes per minute.   2. Changing the position of the first zone relative to the third zone includes linearly increasing a difference in the position of the first zone relative to the third zone in the extending direction over the extending distance. The method of any one of 2, or 4-10.   12. A method according to any one of claims 2 to 11 wherein all of the web in the second zone is stretched. A web path comprising a down-web direction extending from the input end to the discharge end and a cross-web direction transverse to the down-web direction, wherein the web path comprises first, second and third zones. Further comprising: each of the first, second, and third zones includes a portion of the width of the web path and extends along the length of the web path in a down-web direction; A web stretching device comprising a web path positioned between the first zone and the third zone,
The first zone and the third zone have a neutral position relative to each other in which the first, second and third zones are aligned in the cross-web direction;
And the first zone and the third zone have stretch positions relative to each other that are displaced from each other in a stretch direction in which the first and third zones are perpendicular to both the down-web direction and the cross-web direction. The web path defines a stretch distance in which the first zone and the third zone are displaced relative to each other in the stretch direction;
And a device wherein the second zone of the web path extends between the first zone and the third zone and is not supported between them over the stretch distance.   The apparatus of claim 13, wherein the first zone has a width that is greater than or equal to the width of the second zone.   15. An apparatus according to any of claims 13 or 14, wherein the third zone has a width that is greater than or equal to the width of the second zone.   16. In any one of claims 13 to 15, wherein at the stretch position, the first zone and the third zone are displaced from each other in the stretch direction by an amount that increases over the stretch distance in the down-web direction. The device described.   17. The stretching zone according to any one of claims 13 to 16, wherein at the stretching position, the first zone and the third zone are displaced from each other in the stretching direction by an amount linearly increasing over the stretching distance in the down-web direction. The apparatus according to item 1.   18. Apparatus according to any one of claims 13 to 17, wherein a first zone of the web path is defined by a first zone belt over the stretch distance.   19. Apparatus according to any one of claims 13 to 18, wherein the first zone of the web path is defined by a pair of opposing first zone belts over the stretch distance.   20. A device according to any one of claims 13 to 19, wherein a third zone of the web path is defined by a third zone belt over the stretch distance.   21. Apparatus according to any one of claims 13 to 20, wherein a third zone of the web path is defined by a pair of opposing third zone belts over the stretch distance.   The apparatus according to any one of claims 13 to 21, further comprising a web separation device in the down-web direction from the discharge end.   The method or apparatus according to any one of claims 1 to 22, wherein the stretching distance is 0.2 meters or more.   The method or apparatus according to any one of claims 1 to 22, wherein the stretching distance is 0.4 meters or more.   25. A method or apparatus according to any preceding claim, wherein the web path lengths of the webs in the first, second and third zones are all equal over the stretch distance.   Over the stretch distance, the web path length of the web in the first zone is different from the web path length of the web in the second zone, and the down-web speed of the web in the first zone is 25. A method or apparatus according to any one of the preceding claims, wherein the web speed in the two zones is different from the web speed. A web comprising an indefinite length and a cross-webwise width transverse to the length, the web further comprising first, second and third zones, wherein the first, second, And each of the third zones includes a portion of the width of the web and extends along the length of the web, and the second zone is located between the first zone and the third zone And
The second zone includes a zone to be stretched, and the second zone has a width of 5 millimeters or more after stretching from the original width, and the first zone is greater than or equal to the width of the second zone A web having a width that is.   28. The web of claim 27, wherein the width of the second zone is 10 millimeters or greater.   29. A web according to any of claims 27 or 28, wherein the third zone has a width that is greater than or equal to the width of the second zone.   30. Any of claims 27-29, wherein the zone to be stretched comprises an elastic activation zone, and further the width of the second zone is measured when the second zone is in a relaxed state after stretching. The web according to item 1.   31. A web according to any one of claims 27 to 30, wherein the first zone is inelastic.   32. A web according to any one of claims 27 to 31 wherein the third zone is inelastic.   33. A web according to any one of claims 27 to 32, comprising a single web.   33. A web according to any one of claims 27 to 32, comprising a composite web.

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